In centrifugal compressors, an impeller is mounted upon a drive shaft and the shaft is rotated at high speeds by a motor acting through a transmission. The drive shaft is typically rotatably supported in one or more roller bearings. Overheating of the bearings can give clear indication that the compressor drive train is experiencing some type of problem that could eventually result in damage to one or more drive components. It is therefore desirable to monitor the temperature of at least one of the support bearings in the impeller drive train so that preventative measures can be taken to insure that the drive system does not become damaged or the compressor require replacement.
One way to monitor the performance of roller bearings is to place a temperature probe in direct contact with the outer race of the bearing. Some probes typically have a fixed length and, as a consequence, contact between the probe and the bearing can be lost due to thermal deformation of parts or mechanical vibrations. Self-adjusting temperature devices are known in the art, however, these devices for the most part, are relatively complex, difficult to install, and susceptible to misalignment problems and breakage.